Oil or fuel coming from the exhaust

[KillRbee18]

Fellow Owners, I have an old Craftsman riding lawn mower (12hp OHV = 38") that is spuming either oil or fuel from the exhaust. What could be causing that?

 

[ILENGINE]

A leaking float valve that has allowed the carb to overflow and then run into the cylinder and out the exhaust could also have oil mixed with it. Also it can run into the crankcase causing it to overfill and dilute the oil causing other issues.